On railway tracks, presence of trains can be monitored by inducing circulation of electrical current within the rails in order to detect, by the variations of the properties of the electrical current, the presence of a train. Such a technique is generally implemented by subdividing the railway track in successive track sections which each form an electrical circuit, which is independently fed with electrical current. The electrical current in the parallel rails forms a closed loop, with electrical connections at each end of the railway track section adapted to connect the parallel rails to each other to close the electric loop. When a train enters the track section, conduction of electrical current in the metallic elements of the train, such as wheels and axles, provokes a short-circuit which prevents electrical current from circulating up to the end of the track circuit located on the side where the train is present. This induces a variation of the properties of the electrical current going in the electrical circuit, these variations denoting presence of a train on the railway track section.
However, such a technique implies that electrical current is continuously fed to the electrical circuit, whereas trains are effectively running on the tracks for a small amount of time. This induces electrical power overconsumption.
It is known, for example from US-A-2013/0264430, to limit the power consumption of wayside electrical equipments when no train is present on the railway track. When a train is detected as entering the track, the electrical circuit is fed with a nominal electrical current for feeding the wayside equipment such as signals or communication devices.
However, when a train enters a track section, the short circuit induced by the train provokes a rise of the power consumption of the track circuit, which increases until the train passes on the end of the track circuit where electrical power is fed to the circuit by a transmitter. This increasing power consumption provokes unnecessary power consumption.